Second-ranked Iga Swiatek defeated world number one Aryna Sabalenka 6-3, 6-2 on Sunday to reach the title match of the WTA Finals, where she will face fellow unbeaten Jessica Pegula.
By downing the reigning Australian Open champion, Swiatek denied Sabalenka a victory that would have clinched the year-end top ranking for the 25-year-old from Belarus.
Instead, reigning French Open champion Swiatek of Poland can claim the year-end world number one spot for the second consecutive season by defeating American Pegula in Monday's championship match.